The present invention relates to a process for the preparation of certain cyclic urea compounds, which have been found to be effective herbicides.
Herbicides have been used for many years by farmers, commercial agricultural companies and other industries in order to eliminate weed pests and thereby increase crop yields of such staple crops as corn, soybeans, rice and the like.
There are a number of different types of herbicides presently sold commercially, and these fall into two general categories. The categories are pre-emergence and post-emergence herbicides. The pre-emergence herbicides are normally incorporated into or applied to the soil prior to the emergence of the weed plants from the coil, and the post-emergence herbicides are normally applied to plant surfaces after emergence of the weeds or other unwanted plants from the soil. Some herbicides are effective both as pre- and post-emergence herbicides. The cyclic urea compounds prepared in accordance with the process of this invention fall into that category.
As used herein, the term "herbicide" means a compound or composition which adversely controls or modifies the growth of plants. By the term "herbicidally effective amount" is meant any amount of such compound or composition which causes an adverse modifying effect upon the growth of plants. By "plants" is meant germinant seeds, emerging seedlings and established vegetation, including roots and above-ground portions. Such controlling or modifying effects include all deviations from natural development, such as killing, retardation, defoliation, desiccation, regulation, stunting, tillering, leaf burn, dwarfing, and the like.